RingBRP/tools/gen-art.mjs

/**
 * Art generation runner.
 *
 * Reads a scenario art prompt sheet, expands its style tokens, and either prints
 * the mj-gen commands or runs them. The markdown IS the source of truth — the
 * prompts are not duplicated here, for the same reason the rules journal is
 * generated from rules.mjs: two copies of a prompt is one copy too many.
 *
 *   node tools/gen-art.mjs                    print every command (default, safe)
 *   node tools/gen-art.mjs --run              actually invoke mj-gen
 *   node tools/gen-art.mjs --only pc_finch    one asset, or a comma-separated list
 *   node tools/gen-art.mjs --only pc_         prefix match works too
 *   node tools/gen-art.mjs --force            regenerate assets that already exist
 *   node tools/gen-art.mjs --sheet <path>     a different prompt sheet
 *
 * --run requires mj-gen on PATH. It is deliberately not the default: this fires
 * paid generations, and forty-three of them is not something to do by typo.
 */
import { readFileSync, existsSync, mkdirSync } from "node:fs";
import { spawnSync } from "node:child_process";
import path from "node:path";

const argv = process.argv.slice(2);
const flag = n => argv.includes(n);
const opt = (n, d) => { const i = argv.indexOf(n); return i >= 0 ? argv[i + 1] : d; };

const SHEET = path.resolve(opt("--sheet", "docs/scenarios/THROUGH_TRAIN_ART.md"));
const RUN = flag("--run");
const FORCE = flag("--force");
const ONLY = (opt("--only", "") || "").split(",").map(s => s.trim()).filter(Boolean);

/* ---------------------------------------------------------------- parse */

const rows = readFileSync(SHEET, "utf8")
  .split(/\r?\n/)
  .filter(l => /^\|/.test(l) && !/^\|\s*-+/.test(l))
  .map(l => l.replace(/^\|/, "").replace(/\|\s*$/, "").split("|").map(c => c.trim()));

const tokens = {};
const assets = [];

for (const cells of rows) {
  if (cells.length === 2) {
    const m = cells[0].match(/^`(\[[A-Z]+\])`$/);
    if (m) tokens[m[1]] = cells[1];
  } else if (cells.length === 3) {
    const m = cells[0].match(/^`([a-z0-9_]+)`$/);
    if (m) assets.push({ id: m[1], label: cells[1], raw: cells[2] });
  }
}

if (!Object.keys(tokens).length) throw new Error(`no style tokens found in ${SHEET}`);
if (!assets.length) throw new Error(`no asset rows found in ${SHEET}`);

/* -------------------------------------------------------------- expand */

const expand = (s, depth = 0) => {
  if (depth > 8) throw new Error(`style token loop: ${s.slice(0, 60)}`);
  const out = s.replace(/\[([A-Z]+)\]/g, (whole, name) =>
    tokens[`[${name}]`] !== undefined ? tokens[`[${name}]`] : whole);
  return out === s ? out : expand(out, depth + 1);
};

const tidy = s => s
  .replace(/`/g, "")
  .replace(/\s*\+\s*/g, ", ")
  .replace(/\s*,\s*,\s*/g, ", ")
  .replace(/\s+/g, " ")
  .replace(/,\s*(--)/g, " $1")
  .trim();

/* Portraits and scenes live in different folders; a numeric suffix means a plate. */
const destOf = id =>
  id.startsWith("pc_") ? "art/portraits"
  : /^tt_\d/.test(id) ? "art/scenes"
  : "art/portraits";

/* ----------------------------------------------------------------- run */

const selected = assets.filter(a =>
  !ONLY.length || ONLY.some(o => a.id === o || a.id.startsWith(o)));

if (!selected.length) {
  console.error(`nothing matched --only ${ONLY.join(",")}`);
  process.exit(1);
}

/* No shell anywhere below: a prompt is full of quotes, commas and double dashes,
   and concatenating that into a command line is how you lose an afternoon. */
if (RUN && spawnSync("mj-gen", ["--help"]).error?.code === "ENOENT") {
  console.error("mj-gen is not on PATH — run this on the machine that has the Midjourney bridge.");
  process.exit(1);
}

let made = 0, skipped = 0;

for (const a of selected) {
  const dir = destOf(a.id);
  const out = path.join(dir, `${a.id}.webp`);
  const prompt = tidy(expand(a.raw));

  if (!FORCE && existsSync(out)) {
    console.log(`skip  ${a.id.padEnd(20)} exists — use --force to regenerate`);
    skipped++;
    continue;
  }

  if (!RUN) {
    console.log(`\n# ${a.id} — ${a.label}\n# -> ${out}\nmj-gen "${prompt}"`);
    made++;
    continue;
  }

  mkdirSync(dir, { recursive: true });
  console.log(`gen   ${a.id.padEnd(20)} ${a.label}`);
  const r = spawnSync("mj-gen", [prompt], { stdio: "inherit" });
  if (r.status !== 0) {
    console.error(`FAILED on ${a.id} (exit ${r.status}) — stopping so you can look at it.`);
    process.exit(r.status || 1);
  }
  made++;
}

console.log(`\n${RUN ? "generated" : "printed"} ${made}, skipped ${skipped}, of ${assets.length} in the sheet.`);
if (!RUN) console.log("Nothing was generated. Add --run on a machine with mj-gen.");